Transformation of Lambert Conic Conformal Coordinates from a Global Datum to a Local Datum

This paper treats the problem of how to transform from global datum, for example, from the International Terrestrial Reference System (ITRS), to a local datum, for example, regional or national, for the practical case of the Lambert projection of the sphere or the ellipsoid-of-revolution to the cone. We design the two projection constants n(ϕ₁, ϕ₂) and m(ϕ₁) for the Universal Lambert Conic projection of the ellipsoid-of-revolution. The task to transform from a global datum with respect to the ellipsoid-of-revolution E_A,B² to local datum with respect to the alternative ellipsoid-of-revolution E_a,b², without local ellipsoidal height, is solved by an extended numerical example. Ideas in this paper could be of interest to those working with maps and coordinates transformation from global geodetic datum to local geodetic datum and vice versa, under the Universal Lambert Conic projection, and applicable to precise positioning and navigation, boundary demarcation and determination in the marine environment.     

A review of algebraic constraints in terrestrial reference frame datum definition

 Station coordinates are combined with velocities estimated by space geodesy techniques to produce the International Terrestrial Reference System. The input is sets of coordinates and velocities calculated by International Earth Rotation Service analysis centers using space geodesy techniques. The working reference system of individual analysis centers is generally conventionally defined. However, the implications of such processing can have an effect on the resulting combined set. The problem of datum definition as a function of coordinate combinations is reviewed. In particular, the problem of minimum constraints is clearly emphasized and the reference system effect is defined. The goal is to build a process that could be used generally to remove uncertainties in the underlying coordinate system without disturbing the underlying information with additional unnecessary information. Received: 25 January 1999 / Accepted: 20 September 2000     

基于SOFA的ITRS与ICRS相互转换方法研究

基础天文标准库(SOFA)是国际地球自转服务(IERS)协议提供的关于地球姿态、时间尺度和历法的一系列程序集;国际地球参考系(ITRS)与国际天球参考系(ICRS)是描述自然天体或人造天体在空间的方向或位置,地面站或运动物体在地球上的位置和运动速度的基础参考系统。本文主要介绍了ITRS与ICRS的发展以及基于SOFA的ITRS与ICRS之间不同的转换方法的实现。     

ITRS/J2000坐标转换误差及其对掩星反演的影响分析

分别对ITRS/J2000转换过程中的极移/潮汐章动、常数偏差矩阵等误差造成的影响进行分析,并分析季节变化、太阳活动、地磁活动等对坐标转换精度的影响。对2019年的IGS精密星历数据进行ITRS地固系转J2000惯性系坐标分析表明,潮汐章动造成的坐标转换误差为0.44 m,春季坐标转换误差(0.23 mm)是其他季节的约3倍;常数偏差矩阵对坐标转换误差可造成1.7 m的影响。对中性大气掩星反演的轨道转换加入误差改正项进行分析表明,潮汐章动和常数偏差矩阵对反演的温度产品分别造成0.09 K和0.19 K的误差影响。建议在进行GNSS无线电掩星反演中采用潮汐章动的高频改正,并且在ITRS/J2000转换过程中推荐将常数偏差矩阵进行旋转处理。     

Transformation of Lambert Conic Conformal Coordinates from a Global Datum to a Local Datum

A detailed gravimetric geoid around Japan has been computed on the basis of 30’ × 30’ block mean free‐air gravity anomalies and GSFC GEM‐8 geopotential coefficient set. The 30’ × 30’ block means were read from various gravity maps around Japan, and the block means have been compiled into the JHDGF‐1 gravity file. Since the gravity file is restricted around Japan (see Figure 1), additional gravity data are needed to perform the Stokes’ integration in the cap with radius ψ₀ = 20°. The 1° × 1° block gravity means have been used outside the JHDGF‐1 region. The remarkable features of the gravimetric geoid occur over the trench areas. The geoidal dents over the trenches amount to ‐20~ ‐25 m in comparison with the geoidal heights in the land areas of Japan. The mean error of the 30’ × 30’ detailed gravimetric geoid obtained is estimated to be around 1.4 m, and the relative undulation of the geoid between the distance of a few hundred kilometers may be more accurate.     

基于IERS 2003规范的坐标系转换实现及其方案应用

主要介绍了IERS2003规范中国际地球参考系(ITRS)到地球质心天球参考系(GCRS)的转换过程,以及与IAU2000决议一致的常规转换公式,并详细分析了以IERS计算程序为工具、“基于CEO”[注]和“基于春分点”的ITRS向GCRS转换的两种等价方案和相应的三种应用方法,最后对新坐标系转换模型的应用进行了探讨。     

国际地球参考框架2000(ITRF2000)的定义及其参数

对国际地球参考框架2000(ITRF2000)的定义、主要参数及其应满足的条件进行了研究,重点指出了它和历史上的各个ITRFyy的不同,并阐述了各个ITRFyy的联系和区别,给出了它们之间相互转换的参数。     

油气勘探中大地坐标系的特点及其应用

概述大地坐标系的定义及国内外常用大地坐标系的特点,并讨论了它们之间的区别与联系,阐述了大地坐标系在海洋油气勘探领域中的应用。WGS84坐标与CGCS2000坐标之间误差极小,二者在油气勘探中可互用。在今后一段时期内,WGS84仍将是油气勘探中所使用的主要坐标系。     

基于 SOFA 的 GCRS 与 ITRS 间坐标转换

协议天球坐标系GCRS是一个准惯性坐标系,在研究卫星运动状态一般都是在这个坐标系下进行。国际地球参考系ITRS是我们常用的坐标系,一般性测量涉及的坐标都是这个坐标系。为了更方便地研究卫星问题,经常需要在这两个坐标系下进行转换。 IAU的标准基本天文程序库SOFA给出基本天文运算的库函数,利用这些库函数,可以方便地实现这两个坐标系的转换。基于SOFA的这些特点,利用C＋＋对GCRS与ITRS的坐标转换进行了研究。     

IERS地球参考系统、大地测量常数及其实现

介绍了国际地球自转服务局（IERS，International Earth Rotation Service）所定义的地球参考系统、大地测量常数及其实现，IERS规范（2003）中一些新的内容．特别是IERS采用国际地球参考系统2000（ITRS2000）后的一些新进展。对ITRS2000的实现,即国际地球参考框架2000（ITRF2000）的定义、主要参数、及其应满足的条件进行了研究，重点指出了它和历史上各个ITRFyy的不同、特色及其联系。